Hello. On the Ubuntu is RSync installed, but i dont know if it is an server.... but why must i rsync install/run on the ubuntu system? i think rsync should running on the omv system?

If the other server is not configured to receive rsync protocol then you can use ssh (if is enabled in the ubuntu machine). But you also need to install rsync in ubuntu, server configuration is not necessary but you will need to setup public key authentication without passphrase.